Yes, light does reach the sky. The sky appears bright during the day because sunlight interacts with the Earth's atmosphere. When sunlight enters the atmosphere, it encounters particles and molecules in the air, such as nitrogen and oxygen. These particles scatter the light in all directions, including downward toward the ground and upward toward the sky.
The scattering of light by the atmosphere is responsible for the blue color of the sky. Shorter wavelengths of light, particularly blue and violet, are scattered more strongly by the molecules in the air compared to longer wavelengths, like red and orange. This scattering causes the blue light to be scattered in all directions, making the sky appear blue to an observer on the ground.
It's worth noting that the atmosphere is not a perfect scattering medium, and some light does pass through to outer space. That's why we can see stars, the Moon, and other celestial objects at night. However, during the day, the scattering of sunlight dominates, giving the sky its characteristic blue color.